1. Department of Physics, Laboratory of Mechanics and Modelling of Physical Systems (L2MPS), Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon
2. Faculté des Sciences et de Technologie, Université des Montagnes, P.O. Box 208, Bangangté, Cameroon
3. Laboratory of Industrial and Systems Engineering Environment (LISIE), IUT/FV Bandjoun, University of Dschang, P.O. Box 134, Bandjoun, Cameroon